The fuel efficiency of an internal combustion (IC) engine depends on many factors. One of these factors is the extent to which the fuel is mixed with air prior to combustion. Another factor that affects fuel efficiency is the amount of air that can be moved through the engine. Backpressure in the exhaust system restricts the amount of air that can be input to the engine. Additionally, most IC engines of the spark ignition type employ a so-called “butterfly” valve for throttling air into the engine. But the valve itself acts as an obstruction to air flow even when fully open.
A variety of devices has been proposed that attempt to provide better fuel-air mixing by imparting turbulence to the intake air. For example, one class of devices utilizes serpentine geometries to impart swirl to the intake air on the theory that the swirling air will produce a more complete mixing with the fuel. Other devices utilize fins or vanes that deflect the air to produce a swirling effect.
For example, U.S. Pat. No. 2,017,043 to Galliot describes a helical groove formed along an interior wall of a pipe, much like the spiral groove formed inside a gun barrel, purportedly to prevent the formation of whirlpools or eddies in the flow of the fluid in the pipe. According to Galliot, by preventing the whirlpools and eddies, the flow of fluid in the pipe can better conform to the interior contour of the pipe. Galliot, however, is not concerned at all of mixing two different types of gaseous and/or liquid material together.
U.S. Pat. No. 4,177,780 to Pellerin discloses a “frusto-conical” element having a perforated wall mounted between the carburetor and the intake manifold of an internal combustion engine to force the fuel droplets in the air/fuel mixture to impact the perforated wall and break up to produce an aerosol, but requires a specific structure, e.g., a “turn,” within the conical element to force the liquid particles of the fuel to impact the perforated wall at a high speed.
U.S. Pat. No. 4,872,440 to Green discloses an air fuel mixing device including a double ring structure, each of which rings having openings to receive air, and the outer ring of which is allowed to rotate with respect to the inner ring, thereby varying the net opening size resulting from the aligning of the respective openings of the rings, to purportedly adjust the air/fuel ratio of the mixture. Green however does not disclose any structure to promote better mixing of the resulting mixture.
U.S. Pat. No. 3,938,967 to Reissmuller discloses a number of helically twisted fin like structures and blades mounted within the throat of an intake manifold of an internal combustion engine, purportedly to produce gyrating air/fuel mixture flow. According to Reissmuller, the gyrating flow of the mixture and non-gyrating flow, resulting from passing straight through a nozzle away from the fins and blades, together produce a turbulence that promotes better mixing. Reissmuller however requires a complex fins and blades, which are difficult to fabricate.
U.S. Pat. No. 5,097,814 to Smith discloses a “tuned air insert” device having a generally tubular shape, which may include surface irregularities. i.e., a rib or flute structure on the internal wall thereof, to “tune” a two cycle engine, i.e., those typically used in gas powered hand tools and model airplanes, at an optimal RPM by adjusting the placement of the device within the air duct leading to the inlet of the carburetor. According to Smith, the placement of the device creates a “venturi effect” in the air within the chamber formed between the device and the inlet opening of the carburetor. By adjusting the size of the chamber, achieved through the adjustment in the placement of the insert device, the two cycle engine is to be tuned for optimal fuel efficiency. However, the tuned air insert device of Smith does not include the features of the present invention that are found to be most beneficial in enhancing fuel efficiency.
Unfortunately, these devices provide less than satisfactory results. What is needed, therefore, is a device that can be easily constructed and is installed into new, as well as existing, IC engines to effectively increase fuel efficiency.